An arson attack early yesterday that caused massive damage to a train at the Ano Patissia station on the Kifissia-Piraeus urban electric railway (ISAP), but no injuries, was claimed later by a new group calling itself Gangs of Conscience, which said it was avenging an acid attack on the head of Attica’s cleaners union in December. According to police, a group of around 30 arsonists wearing Carnival masks torched six wagons of a Kifissia-bound train on the ISAP line at Ano Patissia at around 1 a.m. Police said the masked vandals forced a group of about eight passengers on one train car to get off and then doused the carriage, along with another five, with gasoline before using Molotov cocktail bombs to set them alight. Witnesses said the assailants grabbed the train driver and locked him up with the female station master in the station master’s cabin. In a message posted on the Internet yesterday afternoon, the group said it had carried out the attack in revenge for the assault on 44-year-old Constantina Kuneva in December by two assailants who threw acid in her face. The unionist, a Bulgarian national, has been in the hospital since the attack with damage to her eyes and internal organs. «Sabotage will regain the place it deserves,» said the statement issued by the group, believed to be behind arson attacks on two Attica police stations. It took firemen several hours to extinguish the blaze provoked by yesterday’s attack. Apart from destroying six wagons on the targeted train, the fire also damaged two wagons on another train. An ISAP spokesman said the damage was some 16 million euros. «Each of the carriages is worth 1.5 million euros,» he said. The section of the ISAP line between Eirini and Kifissia was being served by a replacement bus service yesterday.